Water and waste management on passenger transportation vehicles can present challenges. For example, disposing of grey water must be addressed, due to the additional weight associated with carrying the water on-board. This can be a particular concern for passenger airliners.
As background, “grey water” is a term that is generally used to refer to spent water from hand or face washing at a sink basin or faucet. The water may include detergents and soaps from hand washing. The water may also include liquids poured down a drain, such as unconsumed coffee, water, wine, juices, or other liquid items. Managing grey water can present particular challenges onboard passenger aircraft, and a number of solutions have been explored. Some aircraft have disposed grey water overboard, out through drain masts. This presents environmental challenges, due to undesirable materials that may be present in the grey water. This may also present aesthetic challenges, for example, if the grey water is laden with wine or other colored liquids, the colored liquids can “stain” or “paint” the side of the plane as they are discharged. This may also present technical challenges, depending upon the temperature of the liquid to be discharged and the temperature of the atmosphere. Improvements and alternative end uses or end locations for the grey water are desirable.